Every sports car range has its sweet spot - the point in the line-up where performance, value for money and ride versus handling intersect. It's a bit like a dartboard: the bullseye is the spot where all of those considerations merrily converge. The further out you get, past the triples and out towards the doubles, you find the variants that are too stiffly sprung, or too expensive, or not quite powerful enough.
Beyond the edge of the dartboard, beyond even the wooden cabinet where every other one of my darts tend to land, you find the AMG GT R Roadster. In theory this car bundles up all the great things about the AMG GT R coupe with all the best bits of the AMG GT Roadster in one glorious package, but in practice you're left with the worst bits of the GT R coupe (tough ride quality and tyres that hate wet conditions) with everything that's frustrating about the Roadster (like additional weight and the higher cost). All of which means the car you see here is about as far from the sweet spot of the Mercedes-AMG GT line-up as it's possible to get.
But that doesn't necessarily make it a bad car. Just a compromised one. I drove it on one of those days when the sun shines for 15 minutes and your spirits are lifted for a moment, only for a filthy black cloud to roll over the hill and soak everything beneath it before drifting away in the wind, allowing the sun to shine again...for 15 minutes. Repeat until sunset. I tested it along the Oxfordshire/Berkshire border on roads I know well, roads that can turn from wide, smooth and flat to narrow, bumpy and three-dimensional in a heartbeat. On a day like that and on those roads, it's possible to be completely sold on the GT R Roadster and convinced of its virtues one moment, only to hate it passionately the next.
This is a car that's inherently at odds with itself. The GT R is supposed to be the single-minded track-bound car in the AMG GT line-up, the one for which every gram counts and high torsional rigidity is an absolute must. The Roadster is designed to be easy-going by comparison, the one that gets away with carrying a few more pounds around the middle because it serves a very different purpose. Collide those things together and you're left with a machine that's a bit confused about what it's supposed to be. It costs £186,975, making it cheaper only than the extremely hardcore GT R Pro.
I reckon it has more rear-view mirror presence than anything else on the road right now. It looks so wide and low, and that very long bonnet gives it such distinctive proportions. But will a prominent rear wing ever look good on a convertible? You half expect new parents to walk over, grab the wing and push the car along the pavement like it's a pram.
I do like the cabin very much, though. The seating position is very good and the view through the shallow windscreen and across the landing strip of a bonnet is really evocative. The dashboard design is unlike any other car's and the two rows of four buttons on the transmission tunnel, each one with its own tiny digital display, for the most part work well (although it's a small pity the eight round buttons that mirrored the V8 engine configuration have been lost). But I do wonder if you really need two ways of changing the driving mode or traction control setting - currently you can do so using either those buttons in the middle or the controls attached to the steering wheel. In practice you tend only to use the latter.
The decapitation brings with it an 80kg weight penalty, thanks in part to the folding roof mechanism but also the additional bracing that's been slapped on across the front bulkhead, along the sills and behind the seats in order to retain some sort of structural rigidity. The 4-litre twin-turbo V8 is dry-sumped in the AMG GT and here it develops a mighty 585hp. The gearbox is a dual-clutch, slung out beyond the cabin in a translate layout. There's rear-wheel steering, manually adjustable suspension (that's always rather firm) and Michelin Cup 2 tyres.
The roof does its thing in only 11 seconds, at speeds up to 31mph. You do feel quite cool slinging the roof back as you cruise along a busy shopping street, even though you know well enough that everybody watching on is thinking "look at that knob". This car isn't exactly difficult to drive in town, but its width and length, plus the very low-slung seating position, do make it somewhat tricky to navigate through tight spots. And the ride is always very assertive, though never unbearable.
When the AMG GT was new back in 2015 its steering was spookily quick and light. It took mile after mile to tune into its hyperactive rate of response. As the car has been tweaked and developed over the years, the it has improved enormously, and with the GT R's rear-wheel steering and wider tracks front and rear, it's now just-so. At very low speeds you really do feel the rear wheels pivoting in opposition to the fronts, helping the car to carve a really tight turning circle. At higher speeds, meanwhile, the steering just feels natural and accurate.
Even so, this is a car that you have to build up to. You don't just jump in and drive it flat-out right away. I think that's partly because the front axle is such a long way away you don't really have much sense of what it's up to, or how hard it might bite on turn-in. So you start cautiously. Soon enough you work out that as long as the road surface is dry, the Cup 2s will cling to the tarmac like discarded Weetabix to a bowl. There's barely any body roll whatsoever, while body control over a cresting road is absolute.
So there are moments when the GT R Roadster feels inspired. But the instant the road surface turns and the rain falls, it begins to feel nasty. Evil, even. The tough suspension doesn't cope with an uneven road so the car skips and leaps about, while the tyres skim hopelessly across a greasy surface, giving you a sharp fright every time (even in the new 'slippery' driving mode there is rather a lot of leniency built into the traction and stability control systems). It would be no exaggeration to say that in conditions that don't suit it, the GT R Roadster is far too much like hard work and actually no fun at all.
The engine, however, is a titan: instantaneous throttle response, an intimidating amount of power and torque, and what could be the best soundtrack of any turbocharged engine on sale today. It's all V8 thunder and wicked exhaust cracks.
The thing about the AMG GT R, Roadster or otherwise, is that its unyielding chassis and very aggressive tyres give it a narrow operating window. If the conditions suit it, fine. If not, beware. Although the real reason I'm not so sure about this car is that I know other AMG GTs are so much more rounded than it is. If I wanted a head-banging AMG GT, mine would be the wonderful GT R Pro. But I'd actually choose the mid-range, 557hp GT C coupe every single time.
It isn't much slower on paper than the GT R - and probably no slower at all on the road - and it still has the wider tracks with more muscular bodywork and rear-steer, unlike entry-level versions. What's more, its less daft tyres and more forgiving suspension mean you don't have to park up when moody looking clouds gather overhead or avoid bumpy tarmac. It is the sweet spot of the range, right there in the bullseye.
SPECIFICATION - MERCEDES-AMG GT R ROADSTER
Engine 3982cc, V8, twin-turbo
Transmission Seven-speed dual-clutch, rear-drive
Power 585hp @ 6250rpm
Torque 516lb ft @ 2100-5500rpm
0-62mph 3.6 secs
Top speed 197mph
Kerb weight 1710kg